First up, inside the Terminal, we're going to install, using npm install, two modules. We need Expect, which is our assertion library, @1.20.2, and mocha to run our test suite at version 5.0.5. We'll then use the --save-dev flag to add these as development dependencies:
npm install expect@1.20.2 mocha@5.0.5 --save-dev
Let's go ahead and run this command, and once it's done we can move into package.json and set up those test scripts.
Inside package.json we now have our two dev dependencies, and inside the scripts we can get started by removing the old test script. We'll add those two scripts, test and test-watch:
"scripts": {